Ah, I see you are having problems as well. I will try to flash the older firmware in a couple of days, and post back the results. If that still doesn't work, I think I will have to try and test if the OTGW is actually good. I don't have much experience in soldering, so it could be something is not quite right, but since it works good when only otmonitor is connected, I was assuming the hardware-side was okay.

Are there any links on testing the hardware? Because I'm afraid that the older firmware will not be the solution, since (as you already said) many people are running this version in combination with Domoticz.

I just bought an OTGW with firmware 4.2.5. I noticed that it reports only messages of length 9 (like BC0090000) to domoticz (it says 2018-05-18 19:26:48.619 OTGW: BC0090000) while the source-code of domoticz seems to want to parse other output. I guess it is more like the messagelog of otmanager. Maybe older firmware outputs this type. I dont know because it failed to downgrade. Anyhow... I am rewriting the code (OTGWBase.cpp) of domoticz as we speak. I just finished two messageIDs and it works like a charm. ID 0 Status and 1 Control setpoint.

I just bought an OTGW with firmware 4.2.5. I noticed that it reports only messages of length 9 (like BC0090000) to domoticz (it says 2018-05-18 19:26:48.619 OTGW: BC0090000) while the source-code of domoticz seems to want to parse other output. I guess it is more like the messagelog of otmanager. Maybe older firmware outputs this type. I dont know because it failed to downgrade. Anyhow... I am rewriting the code (OTGWBase.cpp) of domoticz as we speak. I just finished two messageIDs and it works like a charm. ID 0 Status and 1 Control setpoint.

Okay, so I decided to test the harware first. I disconnected the gateway from everything, and removed the PIC and octocoupler. Then I started to follow everything described on http://otgw.tclcode.com/debugging.html

All the voltages check out, but I don't register any amps on X1... Now I figured my multimeter might be broken, so I got a 100 ohm resistor, and screwed one end in X1, and then measured the voltage between the other end of the resistor and the other side of X1. I am still measuring the exact same voltage as when I don't have the resistor connected.

I also posted the question on the domoticaforum.eu-forum, and got a response there. I have been able to get through the whole testing procedure, and it looks like my hardware is okay. I did not immediatly suspect that it would not be, because with otmonitor it worked perfectly, but I just wanted to be sure.

It looks like I have to flash the older firmware. @sincze Do you have 3.4 anywhere? I can't find it on the otgw-website.

I have excactly the same problem. everything starts ok but after some hours i only get an endless stream of data from the gateway.
I do not think it has something to with the opentherm firmware. I have an older gateway with the serial/usb connection. It worked for 2 tears in a row using the USB port on teh gateway.
Only when i used a usb/serial to lan converter (ESP8266) the problem occured. When using the otmonitor and the lan setup everything works fine!
I think it has got something to do with the serial to lan communication between domoticz and the otmonitor.

I have excactly the same problem. everything starts ok but after some hours i only get an endless stream of data from the gateway.
I do not think it has something to with the opentherm firmware. I have an older gateway with the serial/usb connection. It worked for 2 tears in a row using the USB port on teh gateway.
Only when i used a usb/serial to lan converter (ESP8266) the problem occured. When using the otmonitor and the lan setup everything works fine!
I think it has got something to do with the serial to lan communication between domoticz and the otmonitor.

Thanks for the information! It seems this problem is more common than I thought...

Any idea as to where the solution should be found in your opinion? Should the gateway firmware be changed, or Domoticz?

I think it has got something to do with the serial to lan communication between domoticz and the otmonitor.

I think you are right. I just finished rewriting the code (everything works flawless now) and discovered I made a terrible mistake. The good side is that I now know the cause of most problems.

I forgot to connect the Tx from my FTDI USB serial device to the OTGW from the beginning. So I only received B and T traffic as described above. It did not even respond to my command like PR=A (duh!). So I rewrote the domoticz code to parse this messages.

It seems that the old code relied on sending PS=1 to get a status report. If there is something wrong with the serial connection (bad signals due to long cables or in my case no Tx signal) domoticz receives nothing at all. It also send more than just one command (PR=G, PR=O and PR=I). This is not a good idea because this generates a lot of responses and everything have to work together. So just listening and not relying on sending a status report command is more error prone.

I attached my code so you can try (on your own risk ). I will review and test it a bit more before submitting it to domoticz github. I also documented the code. I will add more status reports and error handling. (I just finished reading the OpenTherm protocol specification) Hope you will give me some feedback on it so we can improve it more.

I think it has got something to do with the serial to lan communication between domoticz and the otmonitor.

I think you are right. I just finished rewriting the code (everything works flawless now) and discovered I made a terrible mistake. The good side is that I now know the cause of most problems.

I forgot to connect the Tx from my FTDI USB serial device to the OTGW from the beginning. So I only received B and T traffic as described above. It did not even respond to my command like PR=A (duh!). So I rewrote the domoticz code to parse this messages.

It seems that the old code relied on sending PS=1 to get a status report. If there is something wrong with the serial connection (bad signals due to long cables or in my case no Tx signal) domoticz receives nothing at all. It also send more than just one command (PR=G, PR=O and PR=I). This is not a good idea because this generates a lot of responses and everything have to work together. So just listening and not relying on sending a status report command is more error prone.

I attached my code so you can try (on your own risk ). I will review and test it a bit more before submitting it to domoticz github. I also documented the code. I will add more status reports and error handling. (I just finished reading the OpenTherm protocol specification) Hope you will give me some feedback on it so we can improve it more.

I would like to try this out! Is it just a matter of replacing files twith these, or do I have to do something more than that?
Also: if there is anything I can do to help you with this (send log-files, or whatever), I'd be more than happy to do so. Just let me know.

I attached a screenshot. I connected domoticz via otmanager so there is more to see. Oh forgot to say I changed the devices IDs of the switches and sensors in domoticz to the corresponding OpenTherm message IDs. So you need to delete the OTGW devices from domoticz. It will make new devices with the correct IDs.https://imgur.com/a/eMJovpa

I attached my code so you can try (on your own risk ). I will review and test it a bit more before submitting it to domoticz github. I also documented the code. I will add more status reports and error handling. (I just finished reading the OpenTherm protocol specification) Hope you will give me some feedback on it so we can improve it more.

I downloaded the files, but I have been looking around on my RPi, and I can't seem to find these files...

I downloaded the files, but I have been looking around on my RPi, and I can't seem to find these files...
How do I install these?

The are sourcefiles and you need to compile it. Did you install your RPi the easy way or did you compile it from source? If you never done it, maybe I can send you my compiled domoticz file for my RPi if you have the same. I have a RPi 3 B+ and you? The good thing is you can stop your version and start my version for testing. If you put it in a different location you keep your good working version.

I downloaded the files, but I have been looking around on my RPi, and I can't seem to find these files...
How do I install these?

The are sourcefiles and you need to compile it. Did you install your RPi the easy way or did you compile it from source? If you never done it, maybe I can send you my compiled domoticz file for my RPi if you have the same. I have a RPi 3 B+ and you? The good thing is you can stop your version and start my version for testing. If you put it in a different location you keep your good working version.

I installed it the easy way. I'm running a RPi 3, not sure from the top of my head if it is a 3B or not, but definitly bot a 3B+. I'm running raspbian Jessie.

You can send it to me, I'll give it a try, but I will need some pointers on installing it I think.